The present invention relates to a flexible printed circuit board, an ultrasonic probe, and a method of manufacturing an ultrasonic probe.
A flexible printed circuit board (hereinafter referred to as FPC) has been used as internal wirings and part mounting substrates for equipment along with progress in the reduction of size, weight, and thickness of electronic equipment. In FPCs, complicate circuits are formed on a flexible electrically insulative film and since they can be flexed, stacked, folded, twisted, etc., they can effectively utilize the space or enable stereoscopic wirings, and are used, for example, in video cameras, car stereo systems, personal computers and printer heads.
Further, FPCs have been used also in the field of medical equipment. For example, in an ultrasonic probe for transmitting and receiving ultrasonic waves in ultrasonic diagnosis equipment, wiring patterns in FPC are connected with ultrasonic transducers and used. By the use of FPC, space can be saved and stereoscopic wiring is possible in the same manner as described above. Particularly, it is suitable to use in a curved array in which ultrasonic transducers are arranged on a curved surface.
By the way, in ultrasonic waves used in the ultrasonic diagnosis equipment, an optimal frequency is different depending on the diagnosis portion of an object to be inspected. Further, the frequency of ultrasonic waves that can be transmitted generally becomes higher as the size of the ultrasonic transducer decreases. Accordingly, the frequency of the ultrasonic waves transmitted from the ultrasonic transducer is different depending on the width of the ultrasonic transducer. Therefore, ultrasonic transducers of various width are necessary in the ultrasonic probe. For example, the size of an ultrasonic transducer is about from 0.2 to 0.6 mm (refer, for example, to Patent Document 1).
Plural wiring patterns in FPC used for an ultrasonic probe are formed in parallel with each other. Accordingly, it was necessary for forming plural wiring patterns to a base film conforming the distance between each of plural ultrasonic transducers (refer, for example, to Patent Document 2).
[Patent Document 1] JP-A No. 2002-330963
[Patent Document 2] JP-A No. 2006-20297
In the case of using an FPC to an ultrasonic probe, plural wiring patterns in the FPC are connected with plural ultrasonic transducers. Accordingly, it is necessary to form plural wiring patterns to a base film in accordance with the width of plural ultrasonic transducers. However, manufacture of FPC in accordance with the width of the ultrasonic probe requires much labor and cost.